Question

If a car at rest accelerates uniformly to a velocity of 144km/hr in 20sec. Find distance travelled by the car in 1st 20sec

Answer 1

Given:

• Initial velocity = u= 0m/s
• Final velocity = v = 144km/ hour
• Time = t = 20sec

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Need to Find:

• Distance travelled by car in 1st 20 sec=?

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Solution:

v= 144km/ hr

➟ v = $144 \times \dfrac{1000}{3600} m/sec$

➟ v= 40m/s

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We know, from 1st equation of motion that:

v = u + at

➟ a = $\dfrac{v - u}{t} - - - - i$

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We know from 2nd equation of motion that:

$s = ut + \dfrac{1}{2} a {t}^{2} - - - - ii$

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Substitute the value of a from i to ii

$s = ut + \dfrac{1}{2} ( \dfrac{v - u}{t} ) {t}^{2}$

$\implies s = 0 \times t + \dfrac{1}{2} \times (40 - 0) {t}^{2}$

$\implies s = \dfrac{1}{2} \times 40 \times 20$

$\red{\bold{\boxed{\large{\implies s = 400m}}}}$

$\therefore$ Disatnce travelled is 400m

Answer 2

Answer:

Answer is 400m...

Refer the above attachment